Fuel-injection device for internal-combustion engines



J. McKECHNIE.

FUEL INJECTION DEVICE FOR .INTERNAL coIvIBUsTIoN ENGINES.

APPLICATION FILED DEC. 1, 1916. w

A Patented Apr. 27, 1920.

2 SHEETS-SHEET l.

J. M'KECHNIE.

FUEL INJECTION DEVICE FORINTERNAL COMBUSTION ENGINES.

' APPLICATloN FILED 050.1, 1916. I

1,338,316. 'Patented Apr. 27,1920.

2 SHEETS-SHEET 2- gf/SEM 'MM varying the closing of the suction Valve..

' JAMES MOKECHNIE, 0F BARROW-IN-FURNESS, ENGLAND, ASSIGNOR '10 VICKERS LIMITED, 0F WESTMINSTER, ENGLAND.

FUEL-INJ ECTION DEVICE FOR' IN TERNAIJ-COMIBUSTION ENGINES.

Specification of Letters Patent.

Patented Apr. 27, 1920.

Application led December 1, 1916. Serial No. 134,282.

To all whom tmag/ concern:

Be it known that I, JAMES MCKECHNIE, a subject of the King of Great Britain, residing at Naval Construction Works, Barrow-in-Furness, in the county of Lancaster, England, have invented certain new and useful Improvements in or Relating to Fuel- Injection Devices for Internal-Combustion Engines, of which the following is a specif cation. 4

This invention relates to internal combustion engines of the type in which liquid fuel is injected into the worklng cylinder by means of a pump and the chief object ofthe invention is to provide improved means by which the supply of fuel may be controlled so as to give maximuml efficiency for varying load on the engine. I

According to this invention the fuel 1s delivered by a pump giving constant fuel ressure (by the aid, for example, of an adjustable relief valve) and the power of the engine is controlled by varying the perlod of opening of the injection valve, by an adjustable lever operated by a cam the shape 0f which is so -related to the path given to the end of the lever by the adjustment that for all adjustments and `consequent variations in engine power the valve is timed; to open at the correct point at which injection should take place. Independent timing means are therefore dispensed with, the cam being formed to give the proper timing for the operation of the valve for all variations in the period of opening. In the construction preferred the control of the injection valve is effected bya valve lever on an eccentrically mounted pivot which varies the clearance between the lever and the cam and `at the same time displaces the cam roller over the circumference ofthe cam in the desired direction to produce, with the cam, the

roper timing of the valve opening in conjunction with the variation in the duration of the opening which determinesthe power of the engine. The adjustment of the valve lever cam is preferably effected by lever `and., link connections to a control wheel which may act,

pumps so that the output of the pump is,

simultaneously regulated, for example, by

The plump is of larger capacitythan is rel quired by the engine and surplus fuel is discharged through the adjustable relief valve,

'which is s et to give the injection pressure.

The control of the suction of the pump'allows, however, the output of the pump t0 be regulated as the power of the engine is l varied. Excess fuel is always delivered by the pump, so that the pressure to which the relief valve is adjusted is maintained, but the excess over that required by the engine is kept approximately constant, thus assisting the relief valve to maintain a steady pressure. This connection to the fuel pump is particularly desirable for constant speed engines, for example those driving dynamos in which the surplus to b'e passed by the relief valve would otherwise be greatly increased while running at light loads.

In order that the said invention may be clearly understood and readily carried into effect, the same will be described more fully with reference to the accompanying draw in s, in which yigure 1 shows an end elevation of an internal combustion engine fitted with an iny jection control device according to this -invention; and l v Fig. 2 shows the front view of part of a multiecylinder internal combustion engine fitted with. the injection control device.

A is the cylinder cover and B the cylinder supported by the columns C. `D is the crank shaft from which the cam shaft E is driven by any suitable means, such as spiral wh-eels f and f on the intermediate shaft F. .G is the fuel oil irli'ection valve which is operatedI by the cam on the cam shaft E through the lever J, this' lever being mounted on an eccentric fulcrum pin j. This eccentric is controlled by the hand wheel K which partly rotates the rockshaft L through the wormand quadrant lc, this motion of the rockshaft being transmitted to' the eccentric fulcrum pin j by means of levers j, jz of suitable ratio and the link j3.

The cam H and the eccentric pin jare so correlated as to obtain the desired timing of opening of the. fuel injection valve G at all outputs of the engine, z'. e. an approximately constant timing for a constant'speed engine, or an advance or retardation for the corresponding increase or reduction of speed in a variable speed engi-ne. The outline of the cam H is so formed with relation to the timing of the valve for varlous powers hasv valve.

path given by. ad'ustment of the eccentric fulcrum pin j to t e cam roller y" at the end 'of the lever J that, for all clearances between the cam and lever and resulti variation in duration of fuel injection an engine power, the valve is4 timed to open at the correct point aty which injection should take place, Without the introduction o f special timing mechanism. The eccentric vpin j causes adjustment of the roller y" both radiall to the cam shaft E and circumferentia ly of the cam H so that, with proper selection of the roller path and formation of the cam surface, the 4point of opening of the valve G can be determined, in accordance with the requirements ofthe-engine, to givethe maximum efficiency at all owers. In constructions hitherto employe 1f proper been provided for, speciall timing ear has 'been used, independent of the cam, ut as a rule the proper timing is obtained only for normal running of the engine and the eficiency is allowed to fall for substantial changes in power. The control of the timin by the coperation of the cam and-lever adjustment alone`is an essential feature of this invention, in association with'the constant pressure pump.

The fuel is supplied by the battery of high pressure oil pum s M driven off the end of the crank shaft by worm gearing d (Fig. 2) or by any other suitable means and the oil is maintained at a high pressure, substantially constant for all-powers of the engine, by a relief valve N fitted on the fuel discharge pipe m. This relief valve may be set to act -just below the full working pressure required and the pressure of delivery kept constant by controlling the pump in known manner to discharge 1n excess of the requirements of the engine, the excess being discharged through the relief valve, which thusmainta'ins a steady injection pressure.4

For very low powers the pressure may be allowed to fall by suitably reducing the output of the pump or by easing back the relief The control of the pump may be effected through a throttle valve or sleeve O on the suction pipe m of the fuel oil pump or by r varying the period of closing of the suction valve o the pump in a manner already known. The regulation of the ump may be effected simultaneously with t e control ofl the fuel injection valve by suitable link ,work o, o and oz from the rockshaft L. By

thus controlling the pump the relief valve is not called upon to deal with greatly fluctuating-quantlties of excess fuel and the pressure 1s kept steady with great facility.

In a multa-cylinder engine suchas is shown in Fig. 2, the fuel can be supplied from a single pump or set of pumps delivering the fuel to a common supply or pressure,

cylinder engine, can thus be controlled'byvery simple mechanism which effects the timing and duration of the injection without re uiring any special timin mechanism.

he engine shown is of our stroke cycle type (the inlet and lexhaust cams -being omitted for the sake of clearness) but the invention is equally applicable to two stroke en 'nes.

hat I claim and desire to secure by Letters Patent of the UnitedStates is 1. In an internal combustion engine, a liquid fuel injection valve adapted to inject liquid fuel without the use ofcompressed air, a liquid fuel pump adapted to compress the fuel to the pressure of injection and to force it through the injection valve on the latter opening, a relief valve at the discharge side. of the pump adapted to release the fuel above a predetermined pressure so as to maintain the fuel injection pressure constant, means for regulating the supply ofI fuel to the pump, a valve lever, a valve cam mechanism, and a control device connected i' .both to the valve lever adjustment and to the fuel 'admission regulating means of the pump so as to effect simultaneous adjustment of the fuel valvelever and the fuel supplyT to the pump.

2. n an internal combustion engine, a liquid fuel injection valve adapted to inject liquid fuel without the use of .compressed air, a liquid fuel pump connected to the said fuel valve adapted to compress the fuel 1 to the pressure of injection, to maintain such pressure substantial y constant and to force the fuel through the injection valve on the latter o means For' a justin the said valve lever enin a valve lever, a valve cam,-

both radially and circuxnferentially` of the cam to control the engine power by varying the duration of opening of the valve, the surface of the said cam'bein so related to the path of adjustment of t e end of the' valve lever that for all lever adjustments and consequent variations in power of the engine the valve timed to open at the .correct point at which injection should take place, and a connection from the lever adjustment to the suction side of the pump,

- 54 adapted to regulate the output of the said pump in accordance with the engine power. 3. In a 'multi-cylinder internal combustion engine, asingle liquid fuel pump set adaptedv to compress the fuel to the pressure of injection and to force it into the cylinders, a relief valve at the discharge side of the p'ump adapted to-release the fuel above a predeterminedl pressurev so as to maintain thev fuel injection pressure constant, means lfor regulating the suppl -of fuel to the pump, a fuel supply pipe rom the said pump set to'all thel engine cyllnders, a liquid fuel 'injection valve for each cylinder adapted to admit fuel Without the f use of compressed air, a valve lever and cam device for eachf cylinder, Which device comprises an adjustablel valve lever, a valve cam Iand means for adjusting the said valve lever lfect simultaneous adjustment of the fuel valve lever and the fuel, supply to the signature.'

' t JAMES MCKECHNIE.

Inv testimony whereof, I hereto aix my 

